The disclosure relates to an automatic transmission mounted in a vehicle or the like and more specifically to structural allocations of an automatic transmission capable of attaining a multi-stage shift by enabling transmission of a reduced rotation to at least two rotary elements within a planetary gear set and by enabling transmission of an inputted rotation to at least one of the rotary elements.
With the recent demand for improvement in fuel consumption, an automatic transmission mounted in a vehicle or the like has come to be required to have a multi-stage shift. Among such automatic transmissions, Japanese Patent Laid-Open No. 2001-182785 has proposed one capable of attaining the multi-stage shift by having a reduction planetary gear capable of outputting a ‘reduced rotation’ that is attained by reducing an ‘inputted rotation’ inputted to an input shaft and a planetary gear unit having a plurality of rotary elements and by arranging such that the reduced rotation from the reduction planetary gear may be inputted to the rotary elements of the planetary gear unit via, for example, clutches.